Mung Bean Soup

Step 1: Rinse and Soak the Mung Beans

Pick through the dried mung beans to remove any stones or debris, then rinse under cold running water until the water runs clear. Transfer to a large bowl, cover with plenty of cold water, and soak for 2 hours (or overnight in the fridge). The beans will swell to roughly double their original size, which significantly reduces cooking time and helps them burst open more easily during simmering.

Step 2: Boil the Soaked Beans

Drain the soaked beans and transfer to a stainless steel or ceramic pot (never use iron it reacts with the beans and turns the soup dark red). Add 1500ml of fresh cold water and a pinch of salt. Bring to a full boil over high heat, then immediately reduce to medium-low. The water will turn a beautiful bright jade green almost immediately this is the color you want to preserve.

Step 3: Simmer Until the Beans Burst

Maintain a gentle simmer (small bubbles, not a rolling boil) for 30-40 minutes. Stir occasionally to prevent sticking at the bottom. As the beans cook, they will gradually burst open and release their starch, thickening the soup naturally. The liquid will evolve from watery to silky. If using a pressure cooker, 20 minutes on high pressure achieves the same result. If you prefer a completely clear soup with minimal bean texture, simmer for an additional 10 minutes until beans are very soft and the broth is slightly starchy.

Step 4: Sweeten and Chill

Remove from heat. Add rock sugar () and stir until fully dissolved start with 40g and taste, adding more if desired. For an extra-vibrant green color, add 5ml of lemon juice now. Let the soup cool to room temperature, then cover and refrigerate for at least 2 hours until thoroughly chilled. The soup thickens slightly as it cools and the beans settle. Serve over ice or straight from the fridge in a beautiful glass bowl or tall glass.

Tips

• Use a non-reactive pot: Stainless steel, ceramic, or glass cookware only. Iron or aluminum pots react with the beans' compounds, turning the soup an unappealing rust-red instead of vibrant green.
• Soak overnight for fastest results: If you know you'll want tomorrow, soak the beans overnight in the fridge. This cuts cooking time from 40 minutes down to about 20.
• Keep it bright green: Add a pinch of salt or a few drops of lemon juice when the soup starts cooking this slightly acidifies the water and preserves the vivid green color. Using filtered or bottled water also helps.
• Two styles, one recipe: For a clear "cooling" soup (), stop cooking after 20-25 minutes the broth is bright green, beans are soft but whole. For a "detox" soup (), cook 40+ minutes until beans are fully dissolved and the broth is slightly thick and cloudy.

Prep ahead: Soak the mung beans the night before. The next day, just drain and boil the active cooking time drops from 40 minutes to 20 minutes. The finished soup keeps well in the fridge for up to 3 days.

FAQ

Why did my turn red instead of green?
The most common cause is cooking in an iron or aluminum pot the beans' compounds react with the metal and change color. Use stainless steel, ceramic, or glass instead. Alkaline tap water (common in northern China) can also speed up color change; use filtered water or add a squeeze of lemon to neutralize it.

Can I make this without soaking the beans first?
Yes, but cooking time increases from 30 minutes to 60-70 minutes, and the beans may not burst open as evenly. Soaking is strongly recommended for the best texture and shortest cooking time.

What if I don't have rock sugar?
Regular white sugar works fine, though rock sugar () has a cleaner, less cloying sweetness. You can also use light honey add it after cooking, not while boiling, to preserve its beneficial enzymes.

Is suitable for people with cold constitution?
is considered a "cold-natured" food in traditional Chinese medicine. People with cold hands/feet, frequent diarrhea, or yang deficiency should limit intake or add ginger slices and red dates to the soup to balance the cooling effect.